ライフサイエンスコーパス: attenuation correction

1 es were performed using a PET/CT scanner (CT attenuation correction).

2 anche photodiodes and the need for MRI-based attenuation correction.

3 n was significantly lower than that with the attenuation correction.

4 using filtered backprojection with CT-based attenuation correction.

5 , a transmission scan was first acquired for attenuation correction.

6 (ECG)-gated CT scan that is used to perform attenuation correction.

7 of myocardial perfusion SPECT improves with attenuation correction.

8 acquisition parameters that provide adequate attenuation correction.

9 use of filtered backprojection with CT-based attenuation correction.

10 CT scan provides the attenuation map for PET attenuation correction.

11 ity-maximum image of cine CT for cardiac PET attenuation correction.

12 l respiration-induced misalignment errors in attenuation correction.

13 ntation of CT-based transmission imaging for attenuation correction.

14 y 3.7 mSv from one low-dose CT scan done for attenuation correction.

15 a cardiac insert, using a SPECT system with attenuation correction.

16 PET scanner using transmission source-based attenuation correction.

17 n a PET/CT scanner, using the CT portion for attenuation correction.

18 ontrast agent, and the CT data were used for attenuation correction.

19 e chosen method for image reconstruction and attenuation correction.

20 ed methods for both image reconstruction and attenuation correction.

21 sing iterative reconstruction with segmented attenuation correction.

22 etween images reconstructed with and without attenuation correction.

23 are into PET energy during the process of CT attenuation correction.

24 e appearance of images reconstructed without attenuation correction.

25 pear as photopenic regions in images without attenuation correction.

26 ke disappear in images reconstructed without attenuation correction.

27 at obtained with two-dimensional FBP without attenuation correction.

28 e maximum a posteriori (MAP) algorithm using attenuation correction.

29 with images with two-dimensional FBP without attenuation correction.

30 mization algorithm that included scatter and attenuation correction.

31 tterAC versus nonuniform, transmission-based attenuation correction.

32 ocessed and applied to the emission data for attenuation correction.

33 l-to-noise ratio generally was improved with attenuation correction.

34 ed variation of 20%-25% in the image with no attenuation correction.

35 ructed using ML, with and without nonuniform attenuation correction.

36 ompared using nonuniform, uniform or even no attenuation correction.

37 enuation correction with the ground-truth CT attenuation correction.

38 tative SPECT images achieved with nonuniform attenuation correction.

39 hich offer limited accuracy compared with CT attenuation correction.

40 T-based attenuation correction (CTAC) to PET attenuation correction.

41 agent was used for anatomic localization and attenuation correction.

42 field of view with CT from the GeminiTF for attenuation correction.

43 atlas methods by reducing PET error owing to attenuation correction.

44 ient anatomic accuracy for, for example, PET attenuation correction.

45 did not necessitate additional radiation for attenuation correction.

46 ation of bone lesions despite differences in attenuation correction.

47 ollowed by PET/MR imaging with 2-point Dixon attenuation correction.

48 Quantitative PET imaging relies on accurate attenuation correction.

49 he uncertainties associated with scatter and attenuation corrections.

50 sional filtered backprojection (FBP) without attenuation correction (a common clinical protocol), thr

51 es for magnetic resonance (MR) imaging-based attenuation correction (AC) (termed deep MRAC) in brain

52 tional filtered backprojection (FBP) without attenuation correction (AC) and those reconstructed usin

53 We present an approach for head MR-based attenuation correction (AC) based on the Statistical Par

54 CT-based attenuation correction (AC) for myocardial perfusion PET

55 Attenuation correction (AC) for myocardial perfusion SPE

56 e aim of this study was to determine whether attenuation correction (AC) improved the diagnostic perf

57 Metalic implants may affect attenuation correction (AC) in PET/MR imaging.

58 Attenuation correction (AC) is a critical requirement fo

59 Accurate gamma-photon attenuation correction (AC) is essential for quantitativ

60 Whole-body attenuation correction (AC) is still challenging in comb

61 In routine whole-body PET/MR hybrid imaging, attenuation correction (AC) is usually performed by segm

62 this study was to explore the feasibility of attenuation correction (AC) of myocardial perfusion imag

63 Attenuation correction (AC) of PET images with helical C

64 study was performed to assess the effects of attenuation correction (AC) on overall image uniformity

65 mages were reconstructed with four different attenuation correction (AC) PET with patient CT-based AC

66 TOF) PET data provide an effective means for attenuation correction (AC) when no (or incomplete or in

67 ECT reconstructions have been compared using attenuation correction (AC) with various methods for est

68 patients undergoing stress-only imaging with attenuation correction (AC) would validate the safety of

69 es do not correlate directly with PET photon attenuation correction (AC), and inaccurate radiotracer

70 ies when CT instead of germanium is used for attenuation correction (AC).

71 ruction than with FBP, both with and without attenuation correction (AC).

72 -subset expectation maximization (OSEM) with attenuation correction (AC); OSEM with AC and scatter co

73 The aim of this study was to compare attenuation-correction (AC) approaches for PET/MRI in cl

74 o be considered for implementing an accurate attenuation-correction (AC) method in a combined MR-PET

75 An attenuation correction algorithm was used.

76 change significantly after application of an attenuation correction algorithm.

77 Improved attenuation-correction algorithms and a PET/MR-specific

78 Present attenuation-correction algorithms in whole-body PET/MRI

79 Nonuniform attenuation correction allowed a moderate improvement in

80 nstruction, scatter correction, and CT-based attenuation correction allows quantification of (99m)Tc

81 an integrated x-ray transmission system for attenuation correction, anatomic mapping, and image fusi

82 quence (Dixon) used for MR imaging-based PET attenuation correction and a high-resolution MAVRIC sequ

83 Measured attenuation correction and a standard reconstruction pro

84 rrection, two-dimensional FBP with segmented attenuation correction and a two-dimensional iterative m

85 ause it is not associated with radiation for attenuation correction and allows more accurate dosimetr

86 h-hold examination (VIBE) Dixon sequence for attenuation correction and an unenhanced coronal T1-weig

87 Unenhanced CT scans were acquired for attenuation correction and anatomic coregistration.

88 The integrated CT can be used for attenuation correction and anatomic localization.

89 erpolated breath-hold examination) Dixon for attenuation correction and contrast-enhanced VIBE pulse

90 multaneous PET/MR scanner, using MR for both attenuation correction and depiction of lesion location.

91 to February 2005 has advanced the concept of attenuation correction and electrocardiographic gating i

92 Rb-82 PET or technetium-99m SPECT with both attenuation correction and electrocardiography-gating we

93 data and images reconstructed with CT-based attenuation correction and energy window-based scatter c

94 sisting of stress/rest scans with or without attenuation correction and gated stress/rest images (1,9

95 if the unenhanced CT portion, performed for attenuation correction and lesion localization, provides

96 CT is still frequently used only for attenuation correction and lesion localization.

97 times (3-5 min/field of view) and for CT for attenuation correction and localization with a weight-ba

98 sing (18)F-FDG and a PET/CT scanner (with CT attenuation correction and ordered-subsets expectation m

99 of using 4D NAC PET images for accurate PET attenuation correction and respiratory motion correction

100 of using 4D NAC PET images for accurate PET attenuation correction and respiratory motion correction

101 such time points were reconstructed without attenuation correction and rigidly registered to a refer

102 thod was compared with conventional CT-based attenuation correction and the 3-segment, MR-based atten

103 The simplified narrow-beam attenuation correction and the effective (broad-beam) co

104 ted for attenuation using reference CT-based attenuation correction and the resulting 4-class MRAC ma

105 activity measured with PET/CT when using CT attenuation correction and to report our initial experie

106 cquired transmission data permits nonuniform attenuation correction and when incorporating scatter co

107 SPECT data were reconstructed with CT-based attenuation correction and with full as well as 50% and

108 have shown that, by applying object-specific attenuation corrections and suitable partial-volume corr

109 dium-82 cardiac PET-CT (CT was only used for attenuation correction) and coronary angiography within

110 onal resolution recovery (OSEM-3D), CT-based attenuation correction, and scatter correction.

111 were reconstructed with and without CT-based attenuation correction, and the reconstructed SPECT imag

112 ans and artifact removal in the regions with attenuation correction- and scatter correction-based art

113 Despite different attenuation correction approaches, tracer uptake in lesi

114 Cervical spine reconstructions without attenuation correction are difficult to interpret, becau

115 The advantages of attenuation correction are quantitative accuracy, wherea

116 ults show that TOF PET can remarkably reduce attenuation correction artifacts and quantification erro

117 luate CT image noise and the adequacy of PET attenuation correction as a function of CT acquisition p

118 st differences were calculated with CT-based attenuation correction as a reference.

119 In comparison to nonuniform attenuation correction as the gold standard, uniform att

120 he patient-dependent accuracy of atlas-based attenuation correction (ATAC) for brain positron emissio

121 cted (UC) ZTAC (ZTACUC) and a CT atlas-based attenuation correction (ATAC).

122 ation correction and the 3-segment, MR-based attenuation correction available on the TOF PET/MR imagi

123 LROC curves [A(z,LROC)] 0.13) and segmented attenuation correction (average Az 0.59; average Az,LROC

124 9) compared with two-dimensional FBP without attenuation correction (average Az 0.79; average A(z,LRO

125 F was evaluated from images with and without attenuation correction based on a separately acquired CT

126 Attenuation correction based on asymmetric fanbeam TCT s

127 The results of attenuation correction based on TCTs as short as 1 min w

128 tion correction (NC), (b) conventional Chang attenuation correction based on the interactive determin

129 Explicit attenuation correction based on the transmission scan or

130 For pediatric patients, adequate attenuation correction can be obtained with very-low-dos

131 MR-based attenuation correction causes biases in quantitative mea

132 T images and reduces error in pelvic PET/MRI attenuation correction compared with standard methods.

133 ntial whole-body (18)F-FDG PET with CT-based attenuation correction, contrast-enhanced (ce) CT, and c

134 The absence of CAC on low-dose attenuation correction CT identifies PET/CT patients unl

135 d whether the absence of CAC, using low-dose attenuation correction CT obtained during the PET/CT, id

136 First, a whole-body attenuation correction CT scan was obtained.

137 scoring CT, diagnostic CT of the chest, PET attenuation correction CT, radiation therapy treatment p

138 of CAC was visually assessed using low-dose attenuation correction CT.

139 ts are an established limitation of CT-based attenuation correction (CT-AC) in PET/CT.

140 d pipeline, IDIFs extracted by both CT-based attenuation correction (CT-IDIF) and MRI-based attenuati

141 rtery calcium (CAC) from computed tomography attenuation correction (CTAC) scans performed for hybrid

142 TACUC, ZTACSEC, ATAC, and reference CT-based attenuation correction (CTAC) to PET attenuation correct

143 results due to misregistration of PET and CT attenuation correction data-the frequency, cause, and co

144 in PET images can be caused by inappropriate attenuation correction due to a spatial mismatch between

145 T scans performed for anatomic reference and attenuation correction during PET/CT.

146 ributable to residual uncorrected scatter or attenuation correction error.

147 r-correction error was more significant than attenuation-correction error.

148 , allowed the relative impact of scatter and attenuation-correction errors to be determined.

149 e of respiratory motion causes errors in the attenuation correction factors and artifacts in the atte

150 CT images can be used to generate noiseless attenuation correction factors for the PET emission data

151 Attenuation correction factors were calculated from both

152 ficients to the head model for generation of attenuation correction factors.

153 n maximization (OSEM) without any scatter or attenuation correction (FBP-NATS and OSEM-NATS) or corre

154 hod is described using a (153)Gd-line source attenuation correction for body outline.

155 The literature has validated the concept of attenuation correction for the accurate assessment of at

156 a technique that uses downscatter to provide attenuation correction for these acquisitions and compar

157 In the phantom study, the attenuation correction from helical CT caused a major ar

158 The attenuation correction from the average and from the int

159 the heterogeneous brain phantom, the uniform attenuation correction had errors of 2%-6.5% for regions

160 In PET, transmission scanning for attenuation correction has most commonly been performed

161 ty and attenuation (MLAA) for emission-based attenuation correction has regained attention since the

162 ECG gating and attenuation correction help increase specificity and acc

163 ancers underwent PET/CT with low-dose CT for attenuation correction immediately followed by PET/MR im

164 sed algorithm could improve MR imaging-based attenuation correction in critical areas, when standard

165 odifying Dixon-based MR imaging datasets for attenuation correction in hybrid PET/MR imaging with a m

166 Attenuation correction in hybrid PET/MR scanners is stil

167 serves as a potential solution for accurate attenuation correction in hybrid PET/MR systems.

168 Algorithms for attenuation correction in hybrid SPECT/CT systems have t

169 Nuclear Medicine have recognized the role of attenuation correction in increasing the diagnostic accu

170 metallic implants, to be used for whole-body attenuation correction in integrated PET/MR scanners.

171 sessed the accuracy of 4 methods of MR-based attenuation correction in lesions within soft tissue, bo

172 Apart from drawbacks of MR-based PET attenuation correction in osseous structures and lungs,

173 of uptake on PET images depends on accurate attenuation correction in reconstruction.

174 Thus, the accuracy of MR-based attenuation correction in simultaneously acquired data c

175 The addition of attenuation correction in the presence of extracardiac a

176 mages, confirming the robustness of CT-based attenuation correction in the presence of metallic artif

177 nt a novel technique for accurate whole-body attenuation correction in the presence of metallic endop

178 onsiderable debate about the desirability of attenuation correction in whole-body PET oncology imagin

179 In our series of 13 SLK recipients, attenuation correction increased the measured renal func

180 ifacts do not propagate through the CT-based attenuation correction into the PET images, confirming t

181 dings and may propagate through the CT-based attenuation correction into the PET images.

182 correction in critical areas, when standard attenuation correction is hampered by metal artifacts, u

183 MR-based attenuation correction is instrumental for integrated PE

184 Attenuation correction is recommended to optimize the pe

185 MR-based attenuation correction led to underestimation of PET act

186 filtered backprojection (FBP) with measured attenuation correction (MAC) or iterative reconstruction

187 otocols: (a). 3 initial consecutive measured attenuation correction (MAC) scans, followed by resting

188 obtained with the ultrashort-echo-time-based attenuation correction maps currently used in the scanne

189 volume, thus allowing us to create accurate attenuation correction maps.

190 This review addresses how CT-based attenuation correction may affect the quantitative analy

191 Therefore, STE with nonuniform attenuation correction may also result in reconstruction

192 Even though images without attenuation correction may be desired, these results sug

193 attenuation-corrected images, images without attenuation correction may have locally enhanced contras

194 However, using pure parametric maps for attenuation correction may lead to bias close to certain

195 ted PET/MR instrumentation, such as MR-based attenuation correction, may particularly affect brain im

196 We have developed an automated attenuation correction method that compensates for subje

197 The transmission-based attenuation correction method was compared with conventi

198 hod and the reference standard continuous CT attenuation correction method.

199 Current MR-based attenuation correction methods for body PET use a fat an

200 This paper reviews recent developments in attenuation correction methods for cardiac SPECT perfusi

201 A scatter correction method and 2 attenuation correction methods, all applied to inhalatio

202 Because existing MR-based attenuation-correction methods were not designed specifi

203 SUVR measurements obtained from the 2 attenuation-correction methods were strongly correlated.

204 on as positive or negative regardless of the attenuation-correction methods.

205 ood expectation maximization with nonuniform attenuation correction (MLAC).

206 the reproducibility of standard, Dixon-based attenuation correction (MR-AC) in PET/MR imaging.

207 endent on reliable and reproducible MR-based attenuation correction (MR-AC).

208 sed algorithm with standard 4-class MR-based attenuation correction (MRAC) implemented on commercial

209 MR attenuation correction (MRAC) is generally conducted by

210 ification errors induced by MR imaging-based attenuation correction (MRAC) using simulation and clini

211 This method is compared with (a) no attenuation correction (NC), (b) conventional Chang atte

212 Stent position on attenuation-correction noncontrast CT and CTA was used t

213 e correction (frequency-distance principle), attenuation correction (nonuniform Chang correction or w

214 tudy were to develop a method for nonuniform attenuation correction of 123I emission brain images bas

215 r compensating for respiratory motion in the attenuation correction of cardiac PET studies.

216 CT images are intended for use in nonuniform attenuation correction of cardiac SPECT data.

217 col for acquiring a fast TCT can be used for attenuation correction of cardiac SPECT imaging.

218 the effects of patient motion on nonuniform attenuation correction of cardiac SPECT when the transmi

219 Attenuation correction of MR/PET images was segmentation

220 have been proposed in the past for MR-based attenuation correction of PET data, because of their abi

221 CT images were then used for attenuation correction of PET emission data.

222 going technologic challenges (e.g., accurate attenuation correction of PET images) but also to the co

223 Other benefits initially included attenuation correction of SPECT reconstructions, ultimat

224 Fully corrected scans with attenuation correction of the entire chest were availabl

225 Attenuation correction of the filled NEMA phantom was pe

226 for both anatometabolic image formation and attenuation correction of the PET data.

227 n iterative algorithm for reconstruction and attenuation correction of the radionuclide image.

228 , the most prominent being this dataset used attenuation correction of the scintigraphic data.

229 expectation maximization reconstruction, CT attenuation correction) of patients with no known malign

230 a practical transmission scanning system for attenuation correction on a 2-head gamma camera coincide

231 tical approach to TCT imaging for nonuniform attenuation correction on a three-headed SPECT camera.

232 enuation correction to approximately20% with attenuation correction only).

233 was achieved in the liver using scatter and attenuation corrections only, correction for finite spat

234 Use of segmented attenuation correction or three-dimensional acquisition

235 diopharmaceutical problems, lack of measured attenuation correction, or excessive head movement.

236 tenuation correction (CT-IDIF) and MRI-based attenuation correction (pCT-IDIF) were compared with the

237 dicated this artifact was consistent with an attenuation-correction problem caused by misregistration

238 part be explained by inconsistencies in the attenuation-correction procedures.

239 AA coils were not used in attenuation correction processing to emulate clinical PE

240 ay on the patient are often omitted from PET attenuation correction processing, leading to quantifica

241 nium-corrected emission PET images, CT-based attenuation correction produced radioactivity concentrat

242 The PET data were reconstructed using attenuation correction provided by both standard CT and

243 so acquired at the end of expiration for PET attenuation correction purposes.

244 s for diagnostic, anatomic localization, and attenuation correction purposes.

245 The CT scans acquired for PET attenuation-correction purposes were used as reference f

246 were compared with their reference CT-based attenuation correction reconstructions.

247 Attenuation correction reduced the artificially high app

248 Appropriate attenuation correction remains a challenge.

249 The necessity for PET attenuation correction required new methods based on MR

250 BEM uniformity (78% and 89% without and with attenuation correction, respectively [ideal value being

251 47 (87%) and 30 (56%) PHVs with and without attenuation correction, respectively, and the pattern wa

252 Attenuation correction results in many changes in the im

253 iterative reconstruction (IR) with segmented attenuation correction (SAC).

254 ure to compensate for subject motion between attenuation correction scans and emission scans preclude

255 In the present attenuation correction schemes, uncorrected MR susceptib

256 andardized uptake value relative to CT-based attenuation correction (SEG1, -2.6% +/- 5.8%; SEG2, -1.6

257 guration, STE reconstruction with nonuniform attenuation correction significantly improved image unif

258 phantom, STE reconstruction with nonuniform attenuation correction significantly improved uniformity

259 e MRI consisted of 2-point Dixon imaging for attenuation correction, standard sequences for anatomic

260 gate the impact of using a standard MR-based attenuation correction technique on the clinical and res

261 were demonstrated using the current MR-based attenuation-correction technique.

262 sitions and compare it with other recognized attenuation correction techniques.

263 equivalent to PET/CT despite differences in attenuation-correction techniques.

264 We have developed an automated method for attenuation correction that compensates for subject moti

265 ity was nondiagnostic in 81%; after CT-based attenuation correction this decreased to 55%.

266 th datasets to assess the impact of MR-based attenuation correction to absolute PET activity measurem

267 nd liver activity decreased from 90% without attenuation correction to approximately20% with attenuat

268 tudies should at least be reconstructed with attenuation correction to avoid missing regions of eleva

269 d differences between uniform and nonuniform attenuation correction to be in the range of 6.4%-16.0%

270 between CT and PET images, allowing accurate attenuation correction to be performed for respiration-s

271 cal protocol), three-dimensional FBP without attenuation correction, two-dimensional FBP with segment

272 ion followed by filtered backprojection with attenuation correction using a uniform attenuation map.

273 red the SUVs of the PET image obtained after attenuation correction using the patient-specific CT vol

274 Attenuation correction was applied on B-scans to enhance

275 e acquired with a PET/CT scanner, and (68)Ge attenuation correction was applied.

276 No attenuation correction was applied.

277 MR-based PET attenuation correction was compared with CT-derived atte

278 State-of-the-art MRI-based attenuation correction was derived from T1-weighted MRI

279 No attenuation correction was performed on these datasets.

280 n transmission reconstruction algorithm, and attenuation correction was performed using Chang's postp

281 ofile was generated for the case in which no attenuation correction was performed.

282 Furthermore, the effect of attenuation correction was quantified by measuring SUVs

283 uantified from SPECT images without CT-based attenuation correction was significantly lower than that

284 tric-mean quantification with background and attenuation correction was used for liver and lung dosim

285 striatum and background, whereas nonuniform attenuation correction was within 1%.

286 F-FDG PET (dual-head coincidence camera with attenuation correction) was performed before and after 1

287 ion Chang algorithm, modified for nonuniform attenuation correction, was used to further process the

288 ng phenomena in images reconstructed without attenuation correction, we performed a series of simulat

289 Using respiration-correlated CT for attenuation correction, we were able to quantitate the f

290 Images with and without attenuation correction were considered for interpretatio

291 The Dixon MRI sequences acquired for attenuation correction were found useful for anatomic al

292 Coregistration and attenuation correction were performed with CT.

293 using CT performed with 80 kVp and 5 mAs for attenuation correction were visually indistinguishable f

294 foci are visible in images with and without attenuation correction, whereas below the critical value

295 effects on ML reconstruction with nonuniform attenuation correction, which depends on the amount of e

296 82)Rb, a 16-slice PET/CT scanner, helical CT attenuation correction with breathing and also at end-ex

297 rror (RMSE) was used to compare the MR-based attenuation correction with the ground-truth CT attenuat

298 ification accuracy of 3 methods for MR-based attenuation correction without (SEGbase) and with bone p

299 ihood (ML) method incorporating a nonuniform attenuation correction would less likely be affected by

300 ajor challenge of zero-echo-time (ZTE)-based attenuation correction (ZTAC) is the misclassification o